Numerical investigation of forced convection heat transfer through microchannels with non-Newtonian nanofluids

• A numerical heat transfer study of non-Newtonian nanofluids is performed.
• Nanoparticle does not have significant effect on dimensionless velocity profile.
• As the Reynolds number is increased, the pressure drop increases further.
• Thermal resistance of microchannel decreases with using nanoparticle.
• We report significant enhancement of heat transfer by using nanoparticles.

In this paper, convection heat transfer and laminar flow of nanofluids with non-Newtonian base fluid in a rectangular microchannel have been investigated numerically using two-phase mixture model. This research investigates the advantages of using nanoparticles in non-Newtonian fluids with particles size equal to 30 nm. The factor that makes nanoparticles feasible is the significant increase in rate of heat transfer within the fluids that are common in today's industry. The power law model is used both Newtonian and non-Newtonian fluids. The flow behavior and rate of heat transfer performance of microchannel heat sink have been taken into account by looking into the effects of Al2O3 nanoparticles concentrations, Peclet number and flow behavior index. Our results demonstrate significant enhancement of heat transfer of non-Newtonian fluids using nanoparticles particularly in the entrance region. By increasing the volume fraction, higher heat transfer enhancement can be observed. The thermal resistance with Peclet number of 700 and 4% volume fraction reduces approximately 27.2% with shear thinning non-Newtonian base fluid and pressure drop will increase approximately 50.7%. Further analysis on particles type effect is also implemented with Al2O3 and CuO nanoparticles.